Recently I read an interview with Vittorio Storaro, in which the great cinematographer referred to his film, Caravaggio. This was news to me - did Storaro shoot Derek Jarman's Caravaggio, and how could I have missed such an essential piece of film trivia?

It was a different film about Caravaggio, of course. What was interesting was that neither Storaro's American interviewer, nor the editor of the piece, bothered to mention Jarman's film. It's more than 20 years since Jarman's Caravaggio was made. Year by year, film by film, film-maker by film-maker, the pace of forgetting, the erasure of works of art, and bodies of work, accelerates.

Jarman was thought of, for a while, as the "punk" film-maker: a nomenclature that probably amused more than annoyed him. Punk started in 1976 or earlier, but 1977 has been decreed the "official" year of its birth. Jarman's Jubilee was made in 1977; that fortuitous date, plus its apocalyptic landscape and cast of punk scenemakers Wayne County, Toyah Willcox, Adam Ant, and the original Jordan, have made it the "official" punk film.

Was it really that? Splitting spiky hairs, isn't Julien Temple's The Great Rock'n'Roll Swindle a more authentic document? Temple was really there, filming as the Sex Pistols fell apart; Malcolm McLaren, Steve Jones, Paul Cook and Sid Vicious were actors in their own movie. What is/was punk cinema? Was there any? Does it matter today? It depends how you define punk, and that brings us to the fork in the road: was punk real, or otherwise?

After the Sex Pistols collapsed, McLaren, their manager, declared that punk - or at least the Pistols' part of it - had been a joke, a faux-phenomenon to wind up the bourgeoisie while making loads of money. This is the message he conveys in Temple's film. McLaren as mastermind, as Mephistopheles: he plays the part well. Abbe Wool and I bought into this version of his character entirely, when we wrote the screenplay for Sid and Nancy.

The idea that punk was a cynical exercise aimed only at extracting money seemed to be Johnny Rotten's message, too. Though he avoided the Swindle, viewing it as Malcolm's gig, who can forget Rotten's taunts to the disappointed punters at the Pistols' final gig - the Winterland, in San Francisco - "Ever get the feeling you've been cheated?"

McLaren's sacking of the band's bass player, Glen Matlock, in favour of one Sid Vicious, seems like an entirely old-school music-industry tactic. Matlock was - in the early days of the band - the only Sex Pistol who could play an instrument. But Vicious was a skinny youth who looked good with his shirt off: what did it matter that he couldn't play a note or hold a tune? In this cynical, money-hungry vision of punk, the Sex Pistols were no different from the Monkees, whose songs they enthusiastically learned to play.

But, even if the Pistols were the Monkees remanufactured for a narrower market, there were many punks and many inter-punk tendencies. And in those other parts of punk can be found the antidote to Rotten's and McLaren's claims that it was all about money. These were attempts at the creation of a movement: love amid the ruins. This was what appealed to me about punk - the politics and the communality, and the potential for creating something. It is, for all its bleakness, the world of Jarman's Jubilee.

Just because a movement, or an idea, or an act, fails, doesn't make it worthless. Throughout his career, in Spain, Mexico and France, the great film-maker Luis Buñuel made features with a surrealist spirit. Yet he bitterly regretted what had become of the surrealists. "The movement was successful in its details and a failure in its essentials," he wrote. "Surrealism was a cultural and artistic success, but these were the areas of least importance to the surrealists. Our aim was not to establish a glorious place for ourselves in the annals of art and literature - and certainly not in the cinema! - but to CHANGE THE WORLD. This was our essential purpose, and we completely failed."

What Buñuel wrote of the surrealists is equally true of punk. Punk persists, but as a design element or fashion statement: graphics that mimic Jamie Reid's typography, clothes that recall somebody's mum's bold youth. Whether a money-making scam or revolutionary movement, punk was decisively and swiftly killed by the double-whammy of the music business: CDs and pop videos. In the cinema, punk's presence was even more tentative. A handful of independent films dealt with the punk movement, but either confused it with heroin addiction (Christiane F and my own Sid and Nancy) or approached it in an austere and conventional way - Penelope Spheeris' Suburbia. Suburbia had definite empathy for its largely amateur, punk-based cast, yet stylistically it was as conservative, as traditional, as The Beverly Hillbillies or any of Spheeris' later Hollywood films.

Hollywood itself appropriated a "punk look" in Blade Runner and Terminator. But the "look" was all it took: the bleached blond hair of Rutger Hauer and Arnold's leather jacket were artifacts of aryanism and biker-violence that the punk movement had appropriated as a joke. On the surface, the movement envisioned post-apocalyptic mayhem - A-Bomb in Wardour Street, sang the Jam - but at its core, it was anti-violence.

Though not a punk by any means - too old, too wise, too affable - Jarman flew the punk flag in the British cinema. He did this, for as long as he was able, by breaking rules. Hence the anachronisms - the computers and the cars - in his original Caravaggio. Hence his rejection of a "straight" Hollywood career route, and his return to Super 8mm. Hence his last film - made after he went blind - an entirely blue screen and a cornucopia of music and sounds. Blue sounds like some tedious gallery exhibition, but Jarman was a real feature film-maker, and, against the odds, his final experiment succeeded.

What would a punk cinema look like, if one still existed? I think it would be like Jarman's cinema in one way only: that it would be deliberately transgressive, and rule-breaking. Sebastiane was made a year before the "official" debut of punk - but how else can one describe a sexy British gay film set in ancient Rome and acted in Latin? Only "punk" fits the bill. This is not to say that punk cinema must be acted in dead languages, or feature gay erotica, or bait the censor - though these are all admirable things. But a punk cinema would quickly find new ways of transgressing, and of offending.

Here are some ways of doing this:

1. Break rules. Especially media conventions and barriers. Remember the Sex Pistols' infamous appearance on Bill Grundy's Today show. Not only did Steve Jones say "you fucking rotter" but he said it to camera. In mainstream drama or talk show hosts, "objects" are not meant to address the camera. Only "subjects" - Bill Grundy, Alan Yentob, Jonathan Ross - may do this. These hierarchical media rules are strictly enforced by media gatekeepers, as Peter Watkins - surely the icon of punk film-makers! - has observed. By staring directly at the camera, and ignoring Grundy, the Sex Pistols did something more transgressive than merely swearing.

2. Break genres. The critics hate this! Oh, they pretend to like "edgy, ground-breaking cinema", but in reality what every film critic likes best is a big plate of aristocratic stodge, set in a country house, attended by butlers, no surprises anywhere. Give them their country house full of generic characters - then have it mobbed by anarchists, or set fire to it, or better, yet, have the servants flee and leave the toffs trapped in the drawing room, driven mad by unknown psychic terrors, unable to leave ... Or show 'em a documentary, and half-way through, have it become a drama ...

3. Make it cheaply. This is really important. Feature films can be made on film or digital video. Both are excellent media for telling stories. One is vastly cheaper than the other, in production and distribution terms. The zenith of the punk movement came when bands started producing their own tapes and vinyl, and cut out the record companies. Now this has happened with what we call "film". Ignore competing formats or claims of "superior" high-def technology. David Lynch shot his last feature on low-def video, on a camera you couldn't give away - the PD-150. If it's good enough for David, why not us?

4. Make it democratically. No, I don't mean take a vote on how the actors say their lines. I mean that a self-selecting, self-generating punk cinema will open up the barriers that keep the film community mostly white, mostly male, and London-based. As far as entry-level positions go, the London industry is, as ever, utterly nepotistic. It's too small to be otherwise. If you live in Bradford, or Nottingham, or Cardiff and you want to make films, give London a miss. Treat it as a given, collaborate with your fellows, and make your own films.

5. Remember the Clash, singing about how they were so bored with the USA, while repeatedly trying to break into the American market? Try to be more consistent, please. An independent artist of any kind isn't apt to earn much money. Being a radical, anarchist, pacifist, post-punk cineaste is like taking a vow of poverty - though not celibacy. Remain consistent, dedicated, risk-taking, and adventurous. You may make good punk films, and you will certainly have a good time.